I think you have put your finger on the problem there though. If someone has a lot of rep it is, true, a reliable indicator that they will be trustworthy. But, if they don't have much rep it isn't a reliable indicator of anything much. Not when it comes to buying and selling anyway.
It'll take a long time before giving rep is ever a regular part of a transaction. If it ever does.
So at the moment I think all we can do is say; lots of rep means you can trust them. Lack of rep means you should just carry on as would have done before.
I think you have put your finger on the problem there though. If someone has a lot of rep it is, true, a reliable indicator that they will be trustworthy. But, if they don't have much rep it isn't a reliable indicator of anything much. Not when it comes to buying and selling anyway.
It'll take a long time before giving rep is ever a regular part of a transaction. If it ever does.
So at the moment I think all we can do is say; lots of rep means you can trust them. Lack of rep means you should just carry on as would have done before.